Friction shock absorbing mechanism



Nov. 20, 1945. E. H. LEHMAN FRICTION SHOCK ABSORBING MECHANISM Filed NOV. 8, 1943 FRICTION SHOCK ABSORBING MECHANISM Edward H. Lehman, Chicago, Ill., assignor to VW. H. Miner, Inc., Chicago, Ill., a corporation of Delaware Patented Nov. 20, 1945 Application November 8, 1943, Serial No. 509,452

6 Claims.

This invention relates to improvements in friction shock absorbing mechanisms for railway cars.

One object of the invention is to provide a friction shock absorbing mechanism comprising a tions which converge inwardly and present six flat, exterior wedge faces I8-I8, which converge inwardly, each set of two adjacent faces. I8I8 together defining a wedge face of V-shaped, transverse cross section. The hollow wedge block is friction casing;. a pressure transmitting wedge provided with an opening I9 at the inner end block; shoes interposed between the wedgeblock thereof -for a purpose hereinafter pointed out. and interior walls of the casing; and spring re- Rearwardly projecting from the inner side of the sistance means within the casing wherein the front wall IB is a central boss 20 of cylindrical spring resistance includes a central spring elecross section having an exterior spiral groove 2| ment which is employed to anchor the wedge to 10 extending from end to end thereof. `The boss 20 the casing, thereby dispensing with the usual reis in axial alignment with the boss I4 of the taining bolt commonly employed for this purpose. casing and of the same diameter and the spiral A more specific object of the invention is to groove thereof is of the same pitch as thegroove provide a mechanism as set forth in the preceding I5. paragraph, wherein the spring element, which is The friction shoes C, which are three in nurnemployed to anchor the wedge to the casing, is in ber, are interposed between the wedge faces I84 the form of a coil threadedly connected to the of the block B and the friction surfaces I3 of wedge and casing. the casing. Each shoe has an outer friction sur- Other objects of the invention will more clearly face 22 of V-shaped, transverse section, 'engaging appear from the description and claims hereinwith one of the V-shaped friction surfaces of after following. the casing. On the inner side', each shoe has a In the drawing forming a part of this speclficawedge face 23 of V-shaped, transverse section, tion, Figure 1 is a top plan view of a friction engaging with and correspondingly inclined to shock absorbing mechanism embodying my inone of the V-shaped wedge faces formed by two vention. Figure 2 is a longitudinal sectional View, 25 adjacent faces I8-I8 of the block B. At the incorresponding to the line 2-2 of Figure 1. Figure ner end, each shoe has a flat, transverse face 24 3 is a view, similar to Figure 2, illustrating the functioning as a spring abutment. manner of assembling the parts of the mecha- The three spring elements D, E, and F, which-- nism. l form the springvresistance of the mechanism, are

My improved shock absorbing mechanism comdisposed within the casing A. The spring eleprises broadly a friction casing A; a wedge block ment F, which'forms the inner coil of the spring B; three friction shoes C-C-C; and a spring resistance and extends through the opening I9 resistance including three spring elements D, E, into the hollow wedge B, has the front and rear and F, the spring element F' serving also as a end portions thereof threaded respectively on the retaining element to anchor the wedge to the boss 20 of the wedge B and the boss I4 of the casing. casing A, the coils of said front and rear end The friction casing A, which is preferably of portions being seated in the grooves 2l and I5. hexagonal, interior and exterior, transverse cross The pitch of the spiral grooves 2I and I5 prefersection, is open at the front end and closed by a ably corresponds to the pitch of coils of the spring transverse wall I0 at the rear end. The six side 40 in its normal expanded condition. As will be walls of the casing, which are indicated by I I-I I, evident by its threaded connection with the bosses are thickened at the open end of the casing, as of the casing and wedge, the spring F acts to most clearly shown in Figures 2 and 3, said thickanchor the wedge to the casing and limit outwardv ened wall portions providing the friction shell movement of the wedge. The spring element D, section proper of the casing. The friction shell which is relatively heavy, forms the outer coilofl section, which is indicated by I2, presents six the spring resistance and yieldingly opposes inlongitudinally extending fiat faces I3, which conward movement -of the shoes, being interposed verge inwardly of the casing. Each set of two between the end wall Ill of the casing and the adjacent faces I3-I3 together define a fricfiat innerends of the shoes C--C-C. The spring tion surface of V-shaped transverse section. The element E, which is lighter thanthe spring D rear wall ID of the casing is provided with a cenand heavier than the spring F, forms the intertral, inwardly projecting boss I4, of cylindrical mediate coil of the spring resistance and yieldform, having an exterior spiral groove I5 extendvingly opposes inward movement of the wedge B, ing from end to end thereof, forming, in effect, having its front and rear ends bearing respec- 1 an external screw thread. 55 tively on the inner end of the Wedge B and the The wedge B is in the form of a hollow block back wall Ill of the casing, the wedge being proof hexagonal, interior and exterior cross section' vided with a flat wall portion 25 with whichy the hdaving a flat, transverse, front end wall I6. The front end of the spring engages. The wall 25 side walls of the block, which are indicated by surrounds and defines the opening `I9 of the I'I, have inwardly converging, rear, end sec- 6o Wedge. The Spring F, which connects the wedge to the casing, also opposes inward movement of the wedge B, the portion thereof between the bosses I4 and 20 being active toiaccomplish this result.

In assembling the. mechanism, the spring E is first threaded on the boss I4 of the casing. The outer springs D and E and the shoes C are then placed within the casing. After the parts lhave been thus far assembled, the shoes are forced inwardly of the casing against the resistance of the spring D until they reach a predetermined position, this predetermined position being such that the shoes are entirely clear of engagement with the wedge during the operation of assembling the latter with the other parts of the mechanism. While the shoes are held in the predetermined position by a suitable holding tool, the wedge B is applied by screwing the boss I4 thereof into the front end of the spring F. The holding tool f is then disengaged from the shoes, permitting the spring D to expand and force the shoes outwardly against the wedge B which has its movement limited by the anchoring spring F. In the completely assembled` condition of the mechanism, the wedge B is locked against rotation with respect to the casing by the shoes C-C-C, the interengaging` V-shaped, friction surfaces of the shoes and casing. preventing rotary displacement of the shoes with respect to thecasing and the interengaging V-shaped wedge faces of theshoes and wedge, in turn, preventing rotary displacement of the wedge with respect to the shoes. By this arrangement, there is no danger of y the wedge becoming disconnected through accidental unscrewin'g of the spring F from the `bosses Ill4 and 20 of the casing and wedge,

The operation of my improved `shock absorbing` mechanism is as follows: Upon compression of the same the wedge is forced inwardly of the casing, spreading the shoes C--C-C apart and carrying the same inwardly along the friction surfaces of the casing, against the resistance of the spring D. During this action, inward movement of the wedge is resisted jointly by the springs E and F. The desired shock absorbing `capacity is thus provided by combined spring and frictional resistance. i

In release of the mechanism, the springs DY.- E, and F act to restore all of the parts to the normal full release position shown in Figure 2, outward movement of the wedge being limited by the anchoring spring E and'outward movement of the shoes C-C--C, in turn, being limited by the wedge.

I claim:

1. In a friction shock absorbing mechanism the combination with a friction casing; of a friction clutch slidably telescoped within the casing, said clutch including a wedge member and friction shoes surrounding said wedge member, said shoes having interlocking engagement with the wedge and casing to prevent relative rotation of the casing and wedge; and spring means within the casing yieldingly opposing inward movement of the clutch, including a coil spring element hay: ing the coils at the opposite ends thereof in threaded engagement with the casing and wedge member to anchor the wedge member to the casing.

2. In a friction shock absorbing mechanism, the combination with a friction casing of hexagonal, interior, cross section having longitudinally extending, interior, friction surfaces of V-shaped, transverse section; of a plurality of friction shoes having friction surfaces of V-shaped, transverse section interengaged with the V-shaped surfaces of the casing; a central wedge block, said block and shoes having interengaged Wedge faces of V- shaped, transverse section; and spring resistance means within the casing yieldingly opposing inward movement of said shoes and wedge block, including a central coil spring element having threaded engagement with the block and casing, respectively, to anchor the block to the casing.

3. In a friction shock absorbing mechanism, the combination with a friction casing; of a wedge pressure transmitting member; friction shoes having sliding frictiona'l engagement with the casing and wedging engagement with said member; and spring means resisting inward movement of the wedge member and shoes, including a coil spring .element having the coiled portions at opposite ends thereof in threaded engagement with said member and casing to anchor said member to the casing and limit outwardmovement of` vsurfaces thereof, saidl clutch including a wedge block and friction shoes in wedging engagement with each other, said wedge having an inwardly projecting, exteriorly threaded, central boss; and spring means opposing inward movement of the clutch, including a central coil spring element having the coiled portions at opposite ends thereof engaged with the threads of said bosses, respectively, to anchor the block to the casing.

5. In a friction shock absorbing mechanism, the combination with a friction casing closed at the one end by a transverse wall and open at the other end, said casing having interior friction surfaces at said open end; of a threaded control boss on said Wall; a friction clutch telescoped within the casing and having sliding frictional engagement with the friction surfaces thereof, said clutch including a pressure transmitting wedge and friction shoes in wedgingengagement with said wedge; a threaded central boss on said wedge; and spring means within the casing yieldingly opposing inward movement of `the clutch, including a central coil spring having the coiled portions at opposite ends thereof in threaded engagement with said bosses, respectively,

6. In a friction shock absorbing'mechanism, the combination with a friction casing closed vat one end by a transverse wall and open atthe other end; of an inwardly projecting. central bosson said wall, said boss having an exterior thread of spiral groove formation; a frictionclutch telescoped within the casing, s aid clutch including a central wedge block and friction shoes surrounding said block, said shoes having interlocking engagement with the wedge andcasing to hold said wedge against rotation with respect to the casing; an inwardly projecting boss on said wedge, said boss having an exterior thread of spiral groove formation and spring means within the casing yieldingly opposing inward movement of said clutch, including a `central coil spring element having the coiled portions at opposite ends thereof interlocked within the spiral grooves of said bosses, respectively.

EDWARD H. LEHMAN.

CERTIFICATE CF CORRECTION. C Patent No. 2,589,262 November 2C, '19%.

EIMARD H. ILEJHMM.V

l It is hereby certified that erro appear-s in the printed specification of the above numbeed patent requiring Correction as follows: Page 2, seoond Column, line ML, claim 5, for "control" read -C4entral; and that the said Letters Patent should be read'with this` correction therein that the .same may,r Conform to the record of the Case in the Patent Office.

Signed and sealed this 5th day of February, A. D. ll9lL6f (Seal) First Ags e Frazer A Sp' CommissionerI of Patents.

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